Ascorbic acid (AA) is a well known cellular antioxidant that is converted, typically by single electron steps, to its first chemically stable oxidation product, dehydroascorbic acid (DHA). In living cells, DHA is either reduced to AA by glutathione (GSH) dependent reductases, by GSH itself chemically, or is metabolized to 2,3-diketo-L-gulonic acid (DKG) and further degradation metabolites. In a study of the reduction of DHA to AA by rat liver mitochondria, DHA was observed to be converted to L-erythroascorbic acid (EAA) spontaneously. To identify EAA, the purified metabolite was subjected to GC-MS of the trimethylsilyl and acetylated derivatives which permitted its unambiguous identification.